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This 6-page Application Note describes how to use the ADP2384/ADP2386 4-A/6-A synchronous, step-down, dc-to-dc regulators in a synchronous, inverting buck-boost topology to generate negative output voltages from positive input power supplies, without increasing the cost, component count, or solution size. The synchronous topology provides higher efficiency with low output voltages and lower noise under light-load operation. Buck/Boost Regulators Provide Output Voltages Higher, Lower, or Equal To Input AN-1149: How to Apply DC-to-DC Step-Down/Step-Up (Buck/Boost) Regulators DC-to-DC switching converters efficiently change one dc voltage to another. High efficiency dc-to-dc converters come in three basic topologies: step-down (buck), step-up (boost), and step-down/step-up (buck/boost). Buck converters are used to generate a lower dc output voltage, boost converters are used to generate a higher dc output voltage, and buck/boost converters are used to generate an output voltage less than, greater than, or equal to the input voltage. This 8-page Application Note focuses on how to apply buck/boost dc-to-dc converters. Buck and boost converters are described individually in Application Note AN-1125, How to Apply DC-to-DC Step-Down (Buck) Regulators, and Application Note AN-1132, How to Apply DC-to-DC Step-Up (Boost) Regulators. Differential Inputs and Simple LC Filters Reduce Switch-Mode Power Supply Noise AN-1141: Powering a Dual Supply Precision ADC with Switching Regulators Compared with low-dropout regulators (LDOs), switching regulators dissipate less heat and provide higher efficiency, making them well-suited for powering portable devices or nodes in wireless sensor networks. Unfortunately, due to the continuous on-off operation of the power switch, switching regulators generate electromagnetic interference (EMI), as well as ripple and noise at ground and the output rail. In addition to integer multiples of the switching frequency, this noise also occurs at unexpected frequencies. This 8-page Application Note provides tips for powering a precision ADC with switching regulators. Fully Isolated Lithium Ion Battery Monitoring and Protection System (CN0235) Lithium ion (Li-Ion) battery stacks contain a large number of individual cells that must be monitored correctly in order to enhance the battery efficiency, prolong the battery life, and ensure safety. The 6-channel AD7280A devices in this circuit act as the primary monitor, providing accurate voltage measurement data to the System Demonstration Platform (SDP-B) evaluation board; the 6-channel AD8280 devices act as the secondary monitor and protection system. Both devices can operate from a single wide supply range of 8 V to 30 V and operate over the industrial temperature range of −40°C to +105°C. The AD7280A contains an internal ±3-ppm reference that allows a cell voltage measurement accuracy of ±1.6 mV. The ADC resolution is 12 bits and allows conversion of up to 48 cells within 7 μs. The AD8280 functions independently of the primary monitor and provides alarm functions, indicating out of tolerance conditions. It contains its own reference and LDO, both of which are powered from the battery cell stack. The reference, in conjunction with external resistor dividers, is used to establish overvoltage/undervoltage trip points. Each channel contains programmable deglitching circuitry to avoid alarming from transient input levels. The AD7280A and AD8280, which reside on the high voltage side of the battery management system, have a daisy-chain interface, allowing up to eight AD7280A’s and eight AD8280’s to be stacked together and 48 Li-Ion cell voltages to be monitored. Adjacent AD7280As and AD8280s can communicate directly, passing data up and down the stack without the need for isolation. The master devices on the bottom of the stack use the SPI interface and GPIOs to communicate with the SDP-B evaluation board. High-voltage galvanic isolation is required to protect the low-voltage side of the SDP-B board at this interface. The ADuM1400 and ADuM1401 digital isolators and the ADuM5404 digital isolator with integrated dc-to-dc converter combine to provide the required eleven channels of isolation in a compact, cost effective solution. The ADuM5404 also provides isolated 5 V to the VDRIVE input of the lower AD7280A and the VDD2 supply voltage for the ADuM1400 and ADuM1401 isolators. May 2013 High-Side Power Switch with logic-level control
April 2013 Digital Controller for isolated power supplies
March 2013 High-efficiency eight-string white LED Driver for LCD backlight applications
Jon Kraft, Convert a Buck Regulator into a Smart LED Driver, Including Dimming, Analog Dialogue, 2013-03-06 Jon Kraft, Convert a buck regulator into a high-current LED driver, Power Systems Design, 2013-01-26 Mark Cantrell, Optimizing power conversion for isolated sensor interfaces, EDN, 2012-12-04 Maurice O’Brien, Multichannel regulators enable smaller and more reliable embedded power solutions, Electronics Components World, 2012-09-11 Maurice O’Brien, Multichannel regulators enable smaller, more reliable embedded power solutions, New Electronics, 2012-07-10 Solving Isolation Challenges in Power Conversion Applications - This webcast will present solutions to isolation challenges in power conversion applications. Among the topics to be discussed are the limitations of traditional methods of isolation (such as utilization of optocouplers and pulse transformers) vs. more efficient and cost effective solutions that utilize digital isolators. If you are currently using optocouplers and pulse transformers, this is a webcast you should attend. Design Techniques for reducing power consumption and harmful thermal events in industrial designs - This webcast will present: typical analog module configuration and how to calculate the maximum ambient temperature that the system can tolerate, new technology to reduce the power dissipated in the module (regardless of what output load is connected), and the performance of these devices when the supply is run from a switching regulator rather than with a linear regulator. Fundamentals of Designing with Semiconductors: Powering Your Circuit - What is important about a power supply and how does it work? What different types of power supplies and conversion methods are used? How can a power supply affect the signal chain and how do you select the best regulator for your circuit? This webcast will also explain noise, ripple, line and load regulation, power supply rejection ratio, the effects of temperature change, and other specifications that impact power supply performance.
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